1. Field of the Invention
The invention relates to an internal combustion engine, comprising an engine block, a crankshaft rotatably journalled in the engine block, and an auxiliary drive transmission mounted at one side of the engine block. The transmission has an input shaft with an input gear wheel meshing with an output gear wheel driven by the crankshaft and a first output shaft driven by the input shaft for driving at least one auxiliary unit. The auxiliary unit (3) is arranged relative to the engine block (2) so that an upper portion thereof extends above an upper plane (1a) of the engine block.
2. Background of the Invention
Usually, in common internal combustion engines, auxiliary units, such as water pumps, generators, pumps for power steering, and air conditioning, are driven by the crankshaft via pulleys or gear wheels mounted on an end portion of the crankshaft extending outside of the crankcase. The same is true for engine components, such as camshafts and fuel pumps, which often are driven via a toothed pulley and belt at the front end of the engine block. These auxiliary units and the driving assembly, at the front end of the engine, increase the total length of the engine and require space in the engine compartment. Basically, this is not a problem in vehicles having longitudinally mounted engines. But, when it comes to transverse mounted engines, space is more limited, particularly in those having more than four cylinders. For example, those with six cylinders are usually V-engines.
It is known in the art to reduce the space requirements of an in-line engine, e.g., an in-line, six-cylinder engine, by arranging an auxiliary drive transmission (transmission heretofore refers to auxiliary drive transmission) for auxiliary units at one side of the engine. For instance, DE 2 153 773 discloses an in-line, six-cylinder engine having a side mounted transmission with a single output shaft drivingly connected to a fuel injection pump and an air compressor. The generator is conventionally mounted at a high level at one side of the engine block near the front end and is driven by a separate pulley and belt at the front end of the engine block. A starter motor is mounted at a low level of the engine block near the rear end of the engine block.
An internal combustion engine having an engine block (1) and a crankshaft (9) rotatably journalled in the engine block is disclosed. The engine is coupled to a transmission (2) mounted at one side of the engine block. The transmission has an input shaft (6) with an input gear wheel (7) meshing with an output gear wheel (8) driven by the crankshaft and a first output shaft (11, 41) driven by the input shaft for driving at least one auxiliary unit (3). The auxiliary unit (3) is arranged relative to the engine block (2) so that an upper portion extends above an upper end plane (1a) of the engine block. Preferably, the auxiliary unit (3) is an integrated starter/generator, which is drivingly connected to the first output shaft via a two-speed gearbox. An advantage of the present invention is to achieve an internal combustion engine of the type optimized with respect to a compact design. In particular, the auxiliary units coupled to the engine do not increase the length of the package.
More specifically, an advantage of the present invention is to achieve an internal combustion engine which has a compact transmission being able to transmit torque between the engine crankshaft and an integrated starter/generator, a so-called ISG, with a first ratio when the ISG is running as a starter and a second ratio when the ISG is running as a generator.
Another advantage of the invention is that by mounting ISG 3 rather high, the position and weight of ISG 3 assists to force the powertrain to rotate downwards, in the event of a backward movement, thereby forcing the powertrain to move under the passenger compartment.
These and further objects are achieved according to the invention by arranging the auxiliary unit relative to the engine block so that an upper portion thereof extends above an upper end plane of the engine block.
In a preferred embodiment of the present invention, the auxiliary unit is an integrated starter/generator, which is drivingly connected to the engine crankshaft via a two-speed transmission. Such an auxiliary unit is a rather heavy component, and by mounting it so that an upper portion thereof extends above an upper plane of the engine block, its center of gravity is located above the center of gravity of the engine block. Because of the geometrical relation between the engine block and high mounted ISG together with the weight of the ISG causes the powertrain to rotate downwards during its backward movement in the event of a frontal collision, thereby forcing the powertrain to move under the passenger compartment.
Other advantages, as well as objects and features of the present invention, will become apparent to the reader of this specification.